At a bare minimum, you could probably brew with the RO water and be OK. If you have chalk or baking soda I'd add some to keep the pH from getting too low. Assuming this is roughly a 10 SRM beer, I'd go with an RA of about 20-40 ppm CaCO3. Chalk would probably be best since you don't have any calcium in there to begin with.

There is no reason to carbonate/add chalk/baking soda to your brewing liquor.

There is if your water has no akalinity, like when you're starting with RO.

Only if you are brewing a dark beer like a RIS would you need to add alkalinity and in that case I would just use tap water rather than RO water. All you need is the CaCl or CaSO4. Gordon only adds CaCl or CaSO4 to most of his beers per his book and I think he has had one or two beers turn out ok. I think?

It seems rather counter-productive to me to add alkalinity in the form of chark or baking soda when we as brewers are trying to reduce alkalinity and thus reduce our mash pH. Why complicate things by adding back a base when all of the alkalinity has already been removed? Kai has already proven that with DI water and 2-row malt that the mash naturally locks in at about 5.6 and now you want to raise that up by adding alkalinity? The godfather of water, AJ Delange, also agrees that adding alkalinity is rarely needed. The most important things for your mash and yeast are a low pH and calcium. That can be achieved with calcium chloride or gypsum and RO water. By adding chalk or baking soda you would now have to add an acid to undo you base salt addition. If adding alkalinity is truly that important I say just blend 10-20% of you brewing liquor with de-chlorinated tap water. That recipe is fairly pale beer and would turn out just fine with RO water and CaCl or CaSO4 depending on your preference to accentuate the malt or the hops

It seems rather counter-productive to me to add alkalinity in the form of chark or baking soda when we as brewers are trying to reduce alkalinity and thus reduce our mash pH.

It's only counterproductive if you are in fact trying to reduce the mash pH, which is by no means a universal condition. In the OP's situation, he's starting with a water that has no buffering potential at all. When he introduces crystal malt into the grist it will fairly quickly reduce the mash pH out of the desirable range, especially if he's adding calcium salts as you suggest. (And adding sulfate and/or chloride salts for flavor reasons is good advice, as long as it's in conjunction with maintaining the residual alkalinity at a reasonable level, but the OP said he doesn't have access to them at the moment.)

Since you mention Kai Troester, I used his water spreadsheet to work through this example. For a 12 SRM beer and an infusion ratio of 1.8 qt/lb, it estimates a DI mash pH of 5.40. Adding 50 ppm Ca reduces that to 5.35. In this particular case, that's narrowly within the optimum range (5.3-5.8), but it certainly illustrates the point. For a darker beer, adding calcium salts without also adding alkalinity would drop the mash pH out of the optimum range.

It seems rather counter-productive to me to add alkalinity in the form of chark or baking soda when we as brewers are trying to reduce alkalinity and thus reduce our mash pH. Why complicate things by adding back a base when all of the alkalinity has already been removed? Kai has already proven that with DI water and 2-row malt that the mash naturally locks in at about 5.6 and now you want to raise that up by adding alkalinity? The godfather of water, AJ Delange, also agrees that adding alkalinity is rarely needed. The most important things for your mash and yeast are a low pH and calcium. That can be achieved with calcium chloride or gypsum and RO water. By adding chalk or baking soda you would now have to add an acid to undo you base salt addition. If adding alkalinity is truly that important I say just blend 10-20% of you brewing liquor with de-chlorinated tap water. That recipe is fairly pale beer and would turn out just fine with RO water and CaCl or CaSO4 depending on your preference to accentuate the malt or the hops

Alkalinity is a very important addition when the grist requires it. Very few brewers use just 2 row. Malts like roasted grains and crystal grains add far more acidity to the grist than 2 row, and the mash pH can easily drop into the low 5 pH range (room-temp measurement). That low of a mash pH WILL have a negative taste and body impact on the finished beer.

I have had discussions regarding the need for alkalinity in brewing water with AJ and have come to the conclusion that AJ's narrow view of brewing may not provide enough insight into good brewing practice. He is primarily a pale lager brewer and his recommendations are based on that experience. In my experience with a very broad range of brewing styles, I can safely say that there are cases where a brewer should plan for adding alkalinity when their starting water has very low alkalinity (for instance, RO and distilled water).

A case in point. Last weekend I brewed a Dark Mild with 20% medium crystal and 5% light chocolate malts. It is probably one of the most extreme grists I've used. I calculated the brewing water adjustments using Bru'n Water and it indicated I needed a little pickling lime in the mash water since I start with RO water. As a test, I added all the minerals excepting the lime to the mash. After doughing in, the room-temp mash pH measured 5.0 with my calibrated pH meter. My pH goal was 5.3. All pH's should only be discussed at room temperature measurement. For that pH goal, Bru'n Water said I needed to add 0.8 grams of lime. I added 0.6 g after the first pH reading and that moved the pH to 5.2. I added the remaining 0.2 g of lime and the pH ended up at 5.33. That is close enough for me.

As Hoser mentions, if you're adding alkalinity then you would have to add an acid to undo the base addition. He is right, if your adding things like roast or crystal malts, then you're taking care of the alkalinity. I prefer to think of it as adding alkalinity to counter the acid the grist adds. But to each his own.

A proper education on when and how to manage or add alkalinity in your brewing is contained in Bru'n Water.

PS: Brewers that have starting water that is very low in alkalinity should come up to speed with using pickling lime for their brewing water adjustments. Chalk is not a very good alkalinity adjuster.

Are we talking 5.3 at mash temps or room temps? Two completely different things. If it is at room temp than that is well within the range and nothing to worry about, in fact it is ideal.

RO water has a very small buffering capacity as all of the alkalinity is generally not removed. But, yes there is less than 10ppm. You are also forgeting that malt has a natural buffering capacity as well, hence Kai's experiment showing that DI water and 2-Row lock in at approx. 5.6. Color/SRM is a poor predictor of mash pH adjustments (there has been a lot of discussion about this lately) unless one is using dark roasted malts like black patent, roasted barley, carafa, etc. in the case of a stout or porter. You can also get around this issue by cold-steeping the roasted/crystal grains or adding them at sparging to avoid conflicts with mash pH. Crystal 60L will have little effect on mash pH regardless of the water and its alkalinity used. Yes, Martin, I agree with your example of a dark mild, but in your case you are using 25% crystal/chocolate vs. 12.5% crystal 60L in the above recipe. And as I have mentioned above more than once, for a stout or porter I WOULD use water with alkalinity. I am not anti-alkalinity . But for an IPA, it is not needed, look at Firestone Walker's Union Jack. A simple blend of a known percentage of water and its profile is way easier to conrol than adding chalk since it is simple dilution. Especially if he does not have access to any salts at the moment. Plus, chalk must me added in an acidic environment for it to dissolve otherwise it just precipitates out (a mistake a lot of people make by adding it to the brewing liquor). Even with adding a known amount to the acidic mash it will not completeley dissolve. Yes, lime is better choice and probably easier for him to obtain at the moment You can do more harm than good to your beer by playing around with water if you don't know what you are doing. I would just blend 10-20% of his de-chlorinated tap water with his RO water and call it a day. Adjust salts according to desired flavor profile and to provide calcium for the yeast. Besides, Anchor is the bench mark for Cali Commons and I believe San Francisco water is fairly soft, if my memory serves. Hence, the great beers. Now, I don't know if they adjust their alkalinity. But, I bet not.

**EDIT** Yup, just checked. SF water has an alkalinity of 50ppm. Just blend a small percentage of filtered, de-chlorinated water and save yourself the headache of possible messing up your beer.

Are we talking 5.3 at mash temps or room temps? Two completely different things. If it is at room temp than that is well within the range and nothing to worry about, in fact it is ideal.

I think you may have that backwards. A room temp pH of 5.3-5.8 is generally considered optimal, corresponding to a mash temp range of about 5.0-5.5. Unless otherwise specified, pH values are almost always given at room temperature.

You are also forgeting that malt has a natural buffering capacity as well, hence Kai's experiment showing that DI water and 2-Row lock in at approx. 5.6. Color/SRM is a poor predictor of mash pH adjustments

You're certainly correct that attempting to correlate color with mash pH is difficult, but that isn't what I'm doing. I'm using the results from Kai's pH testing, just as you are. If you want to dispute his results for mashes containing crystal malts, that's fine, but I don't think you should use his results for a 100% base malt mash as supporting evidence for that.

Quote from: hoser on Today at 10:31:48 AMAre we talking 5.3 at mash temps or room temps? Two completely different things. If it is at room temp than that is well within the range and nothing to worry about, in fact it is ideal.

I think you may have that backwards. A room temp pH of 5.3-5.8 is generally considered optimal, corresponding to a mash temp range of about 5.0-5.5. Unless otherwise specified, pH values are almost always given at room temperature.

You are correct, I realized I had it backwards after I posted it. Sorry, about that At any rate a pH of 5.3-5.35 would be just fine hot or at mash temp.

I guess my point is that we all know water chemistry fairly well, but the person looking for answers may not. I think we may be making this too complicated for the average brewer or the brewer who doesn't understand water chemistry. More harm can come from adjusting your water than not adjusting your water. I guess my point kind of got lost in this good discussion. Dilution is the easiest method to add or reduce alkalinity. Plus, we are giving advice on water when we don't know the chemistry of morticaixavier's water. Which is what I would like to know. Exactly why is it so bad for brewing that RO water is needed in the first place?